1. Field of the Invention
Embodiments of the invention relate to the field of security alarm systems. More particularly, the present invention relates to an apparatus and method for communication between a security alarm system and a remote monitoring station using reduced data transmission.
2. Discussion of Related Art
Home and business alarms (often referred to as “security systems” or “alarm systems”) typically include several sensors used to monitor unauthorized entry and other conditions at monitored premises, such as fire, smoke, toxic gases, high/low temperature (e.g. freezing) or flooding. These sensors communicate, either wired or wirelessly, with an alarm panel. In response to sensing an alarm condition, a sensor provides a signal to the alarm panel that in turn may sound and notify the occurrence of the alarm to occupants of the premises and remotely signal a monitoring or central station, law enforcement or fire department services. Typically the occurrence of an alarm is signaled to a remote monitoring station that may then dispatch capable authorities to intervene at the premises. For example, in the case of sensing an unauthorized entry to the premises, the monitoring station may dispatch security personnel, typically in the form of private security guards or police officers. Such communication between the premises and the monitoring station has typically taken place by way of the public switched telephone network (PSTN). However, with the advent of other communication networks such as, for example, wireless (GSM/GPRS) and/or Ethernet/Internet, more modern alarm systems utilize these other facilities either in addition to or in place of the PSTN.
Alarm systems communicate with the central monitoring station to confirm that the system is “on-line.” In particular, a “heartbeat” (also referred to as a poll) signal is periodically sent between a communicator housed within the controller and the central monitoring station. This heartbeat may be sent by the central monitoring station or by the communicators at regular intervals. For example, a common UL requirement is for the system to confirm that the communicator or controller is capable of transmitting alarms to the central monitoring station every 200 seconds. However, sending just one heartbeat signal may provide a false indication that the system is off-line since packets sent over GSM and IP networks may be lost.
To overcome this drawback, the communicator may be configured to send several heartbeats within a certain number of seconds to ensure that the receiver at the central monitoring station receives at least one of these heartbeat signals within the given time period. For example, if the requirement is to verify on-line status of an alarm system every 200 seconds, the communicator transmits a heartbeat signal every sixty (60) seconds so that three (3) heartbeat signals are transmitted to the central monitoring station during the given interval. Each of these heartbeat signals includes a certain number of bytes sufficient for the central monitoring station can identify the security system from which the heartbeat transmission originated along with some additional information regarding the system. In addition, the communicator may be configured to communicate with the receiver at the central monitoring station indicating when to expect the next heartbeat signal. However, use of wireless and internet communications to send these heartbeat signals is costly. In particular, these network operators often levy charges depending on whether a data or voice call is placed and how much data is being transferred. Therefore, by sending heartbeat signals at set intervals within a given time interval regardless of whether or not an acknowledgement signal is received from the monitoring station requires the transmission of unnecessary data. Thus, there is a need to provide a communication method that reduces the amount of data being transferred between a communicator or controller of a security alarm system and a central monitoring station while still ensuring on-line notification transmissions consistent with UL requirements.